Interior permanent magnet type rotor having continuous skew structure

Abstract

An IPM type rotor having a continuous skew structure obtained by a simple means, without constituting a permanent magnet as a complicated shape and forming an inclined magnetizing pattern on the permanent magnet. A rotor core has a recess formed on an outer circumferential surface of the rotor core. The recess is formed so as to extend along a boundary line of magnetic poles of a desired skew structure. Therefore, even when each permanent magnet has the cuboid shape, the magnetic flux may be uniformed during the magnetic flux is transmitted through the magnetic steel plate having high permeability, whereby the magnetic flux within the gap having low permeability becomes dominant. As a result, the rotor having the continuous skew structure is obtained.

1 . An interior permanent magnet type rotor comprising:
 a rotor core constituted by stacking magnetic steel plates; and   a plurality of permanent magnets embedded into the rotor core, each of the permanent magnets having a cuboid shape,   wherein a recess is formed on an outer circumferential surface of the rotor core, the recess extending on the circumferential surface while having a portion which extends non-parallel to an axial direction of the rotor so that a continuous skew structure is formed on at least a part of the rotor.   
     
     
         2 . The interior permanent magnet type rotor as set forth in  claim 1 , wherein the recess extends on the outer circumferential surface of the rotor core as a polygonal line. 
     
     
         3 . The interior permanent magnet type rotor as set forth in  claim 1 , wherein the recess extends on the outer circumferential surface of the rotor core as a polygonal line, while partially having a portion which extends parallel to the axial direction of the rotor.